In connecticut state championships, rodrigo runs 1 mile race four different times. he finished with times of a minutes, b minutes, c minutes, and d minutes. what was his average speed, in miles per hour, for all four races combined? a. (a+b+c+d)/4 b.(a+b+c+d)/240 c. (a+b+c+d)/15 d. 4/(a+b+c+d) e. 240/ (a+b+c+d)